Regulator for dynamos



(No Model.)

W. H. ELKINS. REGULATOR FOR DYNAMOS.

No. 505,914. Patented 001;. 3,1893.

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UNITED STATES PATENT OFFICE.

\VILIJIAM H. ELKINS, OF CAMBRIDGE, MASSACHUSETTS.

REGULATOR FOR DYNAMOS.

SPECIFICATION forming part of Letters Patent No. 505,914, dated October 3, 1893.

Application filed November 21 1892- Serial No. 452,685- (No model.)

To all whom it may concern.-

Be it known that 1, WILLIAM HENRY EL- KINS, of Cambridge, in the county of Middlesex and State of Massachusetts, have invented a new and useful Regulator for Dynamos, of

' which the following is a specification, referonce being had to the accompanying drawings, in Which- Figure l is a diagram showing the simplest form of my invention. Fig. 2 is a diagram like Fig. 1 except that two regulating brushes are used. Fig. 3 a diagram like Fig. 2 except that the regulating brushes are differently adjusted.

The object of my invention is to regulate the difference of potential between the terminals of the main circuit and thereby cause the desired current although the resistance varies and my invention is the combination of a regulating brush adjusted in its proper position with a main brush which at full is at its maximum distance from the regulating brush, and which is moved nearer the regulating brush, as the load decreases, both brushes being connected directly with the terminals of the external circuit of the dynamo.

In Fig. 1 I have shown my invention in its simplest form and as applied only to the positive brush of a dynamo; but it will be obvious that it is equally applicable to the negative brush and also that two regulating brushes may be used, one with the positive brush and the other with the negative brush as in Figs. 2 and 3, and this is of course,the better form where the regulation in large dynamos is to be carried below half load.

In the drawings A indicates the armature and a the commutator; B the positive brush and Bthe negative, both connected directly to the binding posts I) and b, and the current from b to b through the translating devices L and field coils f f is to be kept constant, say ten amperes; whether there be many or few translating devices in the circuit 12 L In Fig. 2 I have shown two regulating brushes D D, each adjusted as is the regulating brush D in Fig. l,that is, so that there will be no current, or practically no current through brush D Fig. 1 or brushes D D Fig. 2, at full load; but when the full load is decreased, that is when the resistance decreases, and the current therefore tends to increase, the brush B is moved in Fig. 1 toward brush D, and the current through brush B diminishes while the current through D increases. Say at full load the current through E was ten amperes, and through D nothing; then on a given reduction of load the current through B will be nine amperes and through D one ampere, on a further reduction, eight through E and two through D, and so on until at the minimum load, when the current through B and D is about equal. When a regulating brush D is used with the negative brush B, as in Fig. 2, the two regulating brushes D D will be adjusted in the same Way, that is, with no current through either brush D D at full load, and in that case, Fig. 2, both brushes B B will be moved each toward its regulating brush D and D, as the resistance or load is decreased, with the result that the current through E and B, will fall and through D and D will rise, as above explained.

In Fig. 3 the regulating brushes D D are adjusted so that say at full load, the current is equally divided between D and B and D and B, or, if ten amperes be the constant current desired, five through D and D and five through 13 and B. In this case when the resistance or load is decreased and the current therefore tends to increase, the brushes ]3 B are moved each toward its regulating brush D D and the current through E and B decreases while the current through D and D increases. Practically the regulation cannot be carried to minimum load in that form of my invention shown in Fig. 3; but that is not desirable in all cases. It will now be clear that my invention consists in regulating the difference of potential between the binding posts 12 and b (which are the terminals of the external circuit of'the dynamo, as the whole field and all the translating devices are between I) and b) by means of a regulating brush D and a main brush B both of which are connected directly to terminal b, and the main brush is moved toward the regulating brush as the load decreases, and away from the regulating brush as the load increases; thereby doing away with the variable resistance between the two brushes shown in my Patent No. 412,700, dated Octoher 8, 1889, and also doing away with a variable field as in my Patent No. 460,372, dated September 29, 1891, and othersgranted to me embodying the principle of a portion of the field coils between the main brush and its regulating brush.

I do not claim the combination of a main brush and a regulating brush,bnt Ihave discovered a new principle of regulating dynamos, which consists in varying the diiference of potential between the terminals of the external circuit by moving the main brush nearer to or farther from the regulating brush with both the main brush and the regulating brush connected directly to one terminal of the main circuit.

The main brush may be moved by hand, or by the usual automatic mechanism, indicated in the drawings, but too well known to require description.

What 1 claim as my invention is In adynamo, main brushesBB, regulating brush D, means for moving the main brush B, toward and from the regulating brush D, and an external circuit, one terminal I) of which is directly connected to the main brush B and also to its regulating brush D and which contains the whole field ff and allthe translating devices, all combined and operating substantially as described.

W. H. ELKINS.

Witnesses:

J. E. MAYNADIER, JONATHAN CILLEY. 

